package servlet;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

public class HelloServlet implements Servlet {

    public HelloServlet() {
        System.out.println("1.构造方法");
    }

    @Override
    public void init(ServletConfig servletConfig) throws ServletException {
        System.out.println("2.初始化方法");
        //1，可以获取Servlet 程序的别名servlet -name的值
        System.out.println("HelloServlet程序的别名是: " + servletConfig.getServletName());
        //2，获取初始化参数init - param
        System.out.println("初始化参数username的值是: " + servletConfig.getInitParameter("username"));
        System.out.println("初始化参数url的值是: " + servletConfig.getInitParameter("url"));
        //3，获取ServletContext对象
        System.out.println(servletConfig.getServletContext());
    }

    @Override
    public ServletConfig getServletConfig() {
        return null;
    }

    //servlet方法是专门用来处理请求和响应的
    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
        System.out.println("3.service == Hello Servlet 被访问了");
        //类型转换（因为它有getMethod()方法）
        HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
        //获取请求的方式
        String method = httpServletRequest.getMethod();
        if ("GET".equals(method)) {
            doGet();
        } else if ("POST".equals(method)) {
            doPost();
        }
    }

    /*
    * 做get请求的操作
    * */
    public void doGet() {
        System.out.println("get请求");
    }
    /*
    * 做post请求的操作
    * */
    public void doPost() {
        System.out.println("post请求");
    }

    @Override
    public String getServletInfo() {
        return null;
    }

    @Override
    public void destroy() {
        System.out.println("4.destroy销毁方法");
    }
}
